The traction augmentation art is crowded with a wide variety of devices for the purpose. And many of the devices have seen commercial use. Many have also functioned well for the purpose. But all have suffered from the fact that mounting them on the boss has been a cumbersome process, usually involving a plurality of steps, including a step in which two or more components of the device are fastened together to releasably secure the device about the boss. In the so-called "tire chain art" in particular, this has always been a troublesome problem inasmuch as each tire is commonly engaged with a ground surface thereunder, and to mount the device, it is often necessary either to first lift the tire away from that surface, using a jack under the vehicle, or to first interengage the device between the tire and the surface, by driving the vehicle over it, and then to reach around the outer periphery of the tire to the posterior side thereof, to fasten or otherwise secure the device about the tire before the vehicle can be driven away on that tire. Often too, a further adjustment must be made in the device after the vehicle has traveled a predetermined distance, to assure that the device is tightly engaged about the tire and coaxially aligned with the axle of the wheel. Further adjustments may also be needed at a later time to assure that the device remains tightly engaged about the tire, and is still coaxially aligned with the axle of the wheel.
What is needed then is a device which is mountable so simply on the tire, or on some other boss, as to be engageable about the boss from a position opposite the face thereof, without the use of fasteners. What is needed too is a device of this nature which is both self-tightening and self-aligning once it is mounted on a boss, such as through self-adjustment thereon when the boss is moved in engagement with the interactive surface. Furthermore, the device should be something which is engageable about the boss without an undue amount of strength being needed to engage it on the boss; and also something which should be long lasting and durable in use after it is mounted on the boss. Ideally, it should also be quiet and smooth running when in use on a boss, and as quick and simple to remove as it was to mount on the boss. It should also be highly compactible when removed from the boss and placed in storage.
One object of my invention is to provide a traction augmentation device which meets these requirements, and which in particular, is readily mountable from a position opposite the face of the boss without fasteners, and both selftightening and self-aligning on the boss when the boss is moved in relation to an interactive surface thereopposite. In this way, the user need not do any fastening, tightening, or aligning of the device before he or she can initiate movement of the boss. Another object is to provide a device of this nature which can be mounted on the boss in the same fashion as a pair of rubbers is mounted on a pair of shoes to protect them against mud and snow when walking thereon. Anyone who has mounted a pair of rubbers on his or her shoes, knows that each rubber is commonly mounted on one of the shoes by first gripping one section of the rim extending about the top opening of the rubber and hooking it either about the toe or heel of the shoe, and then stretching the remainder of the rubber away from that point until the whole of the rubber opposes the face of the sole of the shoe, and can be slipped axially upwardly about the body of the shoe and then released to snap engage on the shoe and position the traction augmenting portion of the rubber, i.e., the bottom thereof, opposite the face of the sole of the shoe. He or she also knows that some final adjustment may be needed in the positioning of the bottom of the rubber, to bring it into total registry with the face of the sole, but that often in walking about on the rubber and shoe composite, the rubber will actually self adjust on the shoe until the bottom of it is disposed in full registry with the footprint of engagement between the shoe and a ground surface therebelow. This follows from the tendency of the rubber material to shimmy about on the body of the shoe until it has found a state of equilibrium or stability with the shape of the shoe.
Still other objects will become apparent from the disclosure of my invention which follows hereafter.